Monday, December 29, 2008

Analysis by CHSRA has shown that in order to compete effectively against short-haul flights between the Bay Area and Southern California, the express line haul time between San Francisco and Los Angeles will have to be well below three hours. Given that any acceptable route would also have to serve Central Valley towns with non-express trains and, the desire to leverage Palmdale as a relief airport for LAX, this has led to a requirement to achieve maximum sustained speeds of around 220mph (350-360km/h). The consequence is that CHSRA preferred route calls for approx. 50 daily express trains to barrel through downtown areas of Fresno, Bakersfield and other towns and, do so at the limit of what trainset manufacturers will currently support in commercial service.

Should CHSRA expect strong resistance from residents and businesses located close to its chosen route in the network core?

The main problem is that anything moving that fast creates a great deal of aerodynamic noise. Indeed, the rated power required to overcome wind resistance at high speeds is proportional to the cube of velocity. Most of that power goes toward moving air out of the way, resulting in severe turbulence and hence, in noise. As a first approximation, it's reasonable to assume that noise levels will also increase with the third power of train velocity. Ergo, a train running at 220mph will radiate roughly 1.65 times as much sound power as one traveling at 186mph. At a distance of 50m (~150ft), a TGV train will register a peak of around 92dB in open terrain. The new AGV may be expected to come in at around 94-95dB at that distance and its top speed, though improvements in train aerodynamics may have mitigated the increase.

For reference, a major road at 10m (~30ft) comes in at 80-90dB, a pneumatic jackhammer at 1m (~3ft) at 100dB. In other words, high speed trains are really quite loud, especially if you consider that many railroad rights of way are no more than 100ft (~30m) wide. However, assessing the effect of this noise on the human body and psyche is quite involved. First, the raw sound pressures must be modulated to reflect the fact that the human ear is more sensitive to intermediate frequencies than it is to very low and very high ones. The most common modulation is the "A" weighting curve, resulting in dB(A) values. However, it was developed for sounds that are quiet overall and may therefore not be particularly accurate.

Second, the impact on an average person exposed to the noise depends on the length of exposure, the rate of change in sound power, the spectral distribution and the rate of change of spectral distribution (e.g. due to a Doppler effect). Initially, concentration is most easily broken by sudden, loud noises emitted by fast-moving sources - our stone-age physiology is prone to mistake them for approaching predators or other dangers. Depending on the person, frequent repeat exposure can lead either to acclimatization or, to annoyance. The former refers to a neurological response that mutes the initially present fight-or-flight response, the latter to a negative emotional response to frequent distractions from the task at hand. Activities that require high levels of concentration may favor an acclimatization response, whereas the same person lying still in a hospital bed may suffer acute annoyance. Age is also a factor: children are usually less able than adults to disregard noise events, which can impact their academic performance.

Third, noise tolerance is much lower at night, when most people are trying to sleep. This will be especially relevant to high speed cargo operations on the California network, if any. The increased sensitivity is often accounted for by artificially increasing the severity of nighttime noise events by 10dB(A), corresponding to roughly a factor 3. In general, CSHRA planning at the program level has followed established guidelines to account for all of this in their metrics for predicting likely noise impacts on sections of proposed alignments. However, none of them were developed for ground vehicles traveling at speeds of up to 220mph. CHSRA and other state and federal agencies will likely have to create some new guidelines in the context of this project.

Specific local noise impacts can only be assessed at the project level, as the type of alignment (at grade vs. aerial vs. trench etc.), the type of ballast (gravel vs. concrete) and the presence of nearby buildings all greatly affect how sound is absorbed and reflected in the environment. Structure-borne infrasound, i.e. vibrations below the hearing threshold of ~30Hz, can lead to secondary noise if it causes furniture and items to rattle, though this usually does not apply to high speed lines because their rails are continuously welded.

A much less well understood aspect of high speed train acoustics is the response of animals to repeated noise events. As with humans, for each species and individual there appears to be a spectrum of responses ranging from acclimatization to annoyance to panic reactions. Annoyance effects could range from changes in product quality to increased aggressiveness to obsessive compulsive behavior to reduced fertility. The effect of high speed train noise on small populations of endangered species, e.g. in the Pacheco Pass section between Gilroy and Chowchilla, would be especially difficult to quantify.

Fortunately, at least the trains themselves are easier to study. One tool used to identify noise sources at various frequencies is acoustic tomography. Microphone arrays and software are combined to help engineers figure out which parts of their designs they need to refine further. For example, the pictures below were produced by TNO in the Netherlands to analyze a TGV trainset then under development passing from right to left at 330km/h (~205mph) at a distance of 80m (~250ft). The vertical axis indicates distance from grade level and, the number above each picture reflects the frequency band shown. Note that the horizontal and vertical axes are not shown to the same scale.

Evidently, some of the noise at around 2000Hz is created by the rolling contact of wheels and rails, but most of it originates from the tractor cars at either end - presumably the power electronics. Note that the loudest emissions are from the underside of the trailing car, most likely a result of aerodynamic effects.

At 1000Hz and 500Hz, the ghostly images of the pantographs are visible. Note that the noise sources along the length of the train are located above the wheels at these frequencies, indicated structure-borne sound radiating off the lower edges of the carriages.

At even lower frequencies, the picture becomes harder to interpret. Clearly, the power cars still contribute the bulk of total noise emissions, but there is also a complex acoustic signature from the sides of the carriages. Note how it correlates with the location of the wheelsets, which in an Alstom design are found in-between the carriages (Jacobs bogies). This may be a reflection of the greater stiffness of the side surfaces at those points or, of gaps between the cars.

The sound track of the following video should give you a better appreciation of the individual sound sources, especially the recordings made at the overpass. The whistling sound may be that of air being squeezed sideways at the wheel-rail interface.

The Japanese have developed a variety of nose cone shapes to reduce not just regular noise but also tunnel boom and rail pitting effects related to HSR aerodynamics. Unfortunately, the sexy 500 series performs less well in terms of noise than the cheaper 700 series with its bulbous duckbill nose.

Just for kicks, here is a video of a Caltrain "baby bullet" train storming past a local one at ~79mph with various sound effects. IMHO, if a passenger train is going to make that much noise, it should be at least twice as fast!

The bottom line is that exterior noise will likely be a significant factor in engineering the California HSR system, especially in the Central Valley. In particular, FRA rules prohibiting mixed traffic currently prevent the use of legacy tracks to access stations in downtown areas while routing express trains through open countryside. Note that FRA might make an exception if HSR trains only share track with other passenger trains and their locomotives are upgraded to appropriate safety standards. Unfortunately, that would mean constructing bypass tracks for freight traffic, something Fresno in particular has long sought but never been able to afford.

Worst case, sound walls could be deployed next to HSR tracks to at least reduce noise by as much as 8-15dB (varies with wall height and alignment design). Construction would cost $1-1.5 million per mile, depending on visual appeal. In the context of a $40+ billion project, this may be a small amount compared to the cost and impact of creating brand-new rights of way through prime farmland. After all, HSR ought to improve the quality of life in Central Valley towns beyond merely eliminating horns, bells and danger via grade separation.

On the other hand, it's useful to keep in mind that freight rail operators aren't exactly walking on eggshells right now, even at night. Witness this recent example from east Modesto:

44 comments:

Great post as usual. It seems to me that some of the most complex work on noise mitigation, as with everything else on this project, will come on the Peninsula. I think soundwalls will wind up getting heavily used there and in Central Valley cities.

The impact on wildlife is a huge X factor, particularly in the Pacheco Pass corridor as you note. I can anticipate some suits on that in particular.

I also would not be surprised to see noise mitigation become a major factor in the CHSRA's decision-making on which trainsets to use. Can you provide more specific comments on that?

@ spokker - I suspect the novelty would wear off quite soon if you had to live or work near the tracks. Of course, there's always triple glazing...

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Note that CHSRA could decide to purchase TGV Duplex trainsets for semi-express and semi-local service. They are limited to 186mph but offer almost 50% more seats for only 4% more wind resistance. SNCF is still ordering more of them in favor of the fancy new AGV to meet volume demand for cheap tickets. A 16-car TGV Duplex offers 1090 seats, considerably less than the Japanese E4Max. Then again, JR squeezes in 5, even 6 seats per row in economy class.

At one point, Alstom had even planned to create an unpowered version of the TGV Duplex tractor car for short trainsets plying routes where and/or times at which full 545-seat trainsets could not be justified. Instead of electric motors et al, this version would feature just a driver cab plus a small cafe kiosk plus perhaps some bicycle storage.

There are currently no firm plans for a Duplex version of the AGV, though SNCF would quite like to buy such a beast. Between the EMU concept and the extra weight of the upper floor, it would be extremely difficult to keep axle loads under 17 tons, unless cars were substantially shorter or made from composite materials. Either way, Alstom would be looking at almost a complete redesign.

I don't understand why the HSR should be expected to blast through Fresno at 220MPH. Why don't they build the main right-of-way bypassing the central valley cities, with separate detour tracks serving the downtown area for trains that stop in those cities. This seems to me to make far more sense.

I expect there'll be demand for sound walls south of Fullerton and later on, south of Miramar as well. Speeds there won't be any higher than in the SF peninsula. However, with relatively few freight trains running right now, well-heeled residents along those sections will be quite sensitive to noise.

As for trainsets, every manufacturer will of course claim its products are superior. Afaik, the Japanese have made some of the greatest strides in keeping the noise down in the context of the Fastech 360 development. JR East's original intent was to create a drop-in replacement for its ageing E2 fleet. That meant the new train was supposed to maintain noise emissions and emergency brake distance despite increasing top speed from 275 to 360km/h. In the end, that proved too ambitious. The E5 incorporates a lot of Fastech technology and will be operated at 320km/h. Afaik, Kawasaki is the main contractor. It is also currently developing efSET, a new train that will support 350km/h in Japan.

Note that speeds in Japan are generally lower than in Europe because the original shinkansen network was designed to support speeds of 210-240km/h. Even with EMU technology and active tilting, it is very difficult to push the envelope much further using the existing tracks. In addition, many lines are running close to capacity.

The 700 series shinkansen runs at 285km/h in Japan but is generally considered one of the most advanced trains in the world. The duckbill nose is designed to minimize noise, especially tunnel boom effects and sway resulting from crosswinds and the bow waves of passing trains. Note that the Kawasaki/Hitachi 700T model exported to Taiwan is certified for operation at 350km/h on new track there.

Another manufacturer with a long history of innovation is Talgo in Spain. Its main claim to fame is the use of just a single set of wheels with independent suspension, located in-between unpowered cars (Jacobs configuration, cp Alstom). Fewer wheels means lighter trains and hence, lower power requirements for the same acceleration. The Talgo 350 model is certified to sustain 350km/h in commercial operation on level terrain with a conventional push-pull configuration while keeping axle loads under 17 metric tons. The only reason Renfe is not fully exploiting this speed potential yet is that it does not consider the wireless ETRMS level 2 signaling system to be reliable enough at the present time (cp Taiwan and other countries).

The wheels on Talgo trains are not connected by a fixed axle as usual but rather, able to rotate independently. A passive steering mechanism ensures that each wheelset is always oriented perpendicular to the rails, eliminating squeal noise and greatly reducing wear and tear even in tight bends. In addition, the suspension mount points are located above the center of gravity, so Talgo Pendular trains can reliably support 1-2 degrees of passive tilting for improved passenger comfort in tight bends. All other tilt trains - including the Amtrak Acela Express - use far more complex active tilt systems to support maximum tilt angles of 5-7 degrees.

I don't know enough about the noise characteristics of the Italian ETR500 Frecciarossa and the Korean HSR-350x to comment.

At least the California system will not require any type of tilt technology as its brand-new tracks will be dedicated to HSR service at speeds of up to 220mph. There is no need to compromise on curve radii and track superelevation.

However, mixing European and Asian trainsets on the same network would require agreement on interoperability aspects such as signaling and coupler technology.

what you are proposing would require CHSRA to acquire a brand-new right of way for a direttissima express alignment. In addition, they would also have to construct rather long detour tracks so semi-express and slower trains can serve the downtown stations of Central Valley towns. If target speeds on those detour tracks were above 125mph, FRA would require full grade separation for them as well.

Dedicated detour track would be needed because FRA normally does not permit non-compliant rolling stock - such as the off-the-shelf bullet trains CHSRA quite rightly wants to use - to share track with FRA-compliant trains, especially heavy freight trains. A waiver might be granted if the only other trains on that track were Amtrak San Joaquins, but that would imply shelling out for a freight bypass corridor around Fresno, another around Bakersfield etc.

The Italians do implement the direttissima concept, but then they don't have FRA or mile-long freight trains with double-stacked containers to contend with. Exercising eminent domain against farmland is also a little easier in Europe.

Basically, there's not enough money in the budget to implement the eminently sensible concept you advocate. Plan B and current CHSRA policy is to build a single line without detour tracks. That means figuring out a way to make the noise generated at 220mph tolerable for homeowners just 100 feet or so from the tracks. Technologically and politically, that's a tour de force.

If it proves impossible, express trains would have to run at considerably less that 220mph in the Central Valley. However, doing so would severely undermine key objective of the whole HSR project: avoiding the construction of additional runways at LAX and SFO by shifting short-haul traffic from air to rail.

The other alternative would be to make do with stations at the edge of town in the Central Valley. Amtrak effectively already does this at Modesto E. Briggsmore, but existing rights of way do not permit this option anywhere else. Besides, none of these towns has any light rail systems to provide connecting service and buses aren't popular enough. Driving to an HSR station would be ok for fairly long trips (e.g. to SJ/SF or LA/Anaheim), but the new rail system would then fail to achieve another key objective: avoiding the addition of lanes to hwy 99 by shifting traffic within the CV from road to rail.

I still think these stations need to be on the outskirts of the valley cities just like the TGV so there is no noise problems..I know they want them downtown for future dense housing but if so I bet you there will not be 220mph trains thru these cities.I still think that people in the Valley will drive to the station and want to park just like an airport so these stations will need parking decks. The BNSF would fit this option better..and they are willing to talk

Why can't the train just slow down to 250 km/h before it reaches a major city, then speed up to 350 km/h once it's out of the city? If a train with an acceleration and deceleration of 1.5 km/h/s were to slow down from 350 km/h to 250 km/h before it reaches Fresno (which is assumed to be 25 km long) then speeds back up to 350 km/h once it's out of Fresno, then the extra time cost would only be 2.03 minutes compared to a constant 350 km/h velocity.

the taiwan HSR stations in taichung and tainan are way out on the edge of their respective cities, and they use a free bus to the city centers to make up for than. a lot less convenient than the taipei station, that linked directly into their subway system and went underground for a significant period before the station, but better than nothing.

i couldn't tell much about how the sound was outside the train, but inside it was comparable to being in a very quiet jet, a bit louder in tunnels but generally very comfortable.

now that i think about it, a friend lives near the san jose airport, in a recently built apartment, and san jose had basically required that new buildings had super soundproof windows. you couldn't hear any of the airport noise as long as the windows were closed.

perhaps paying for some soundproofing in houses adjacent to the tracks, as a form of noise abatement, might make life more livable for people close to the tracks? is that sort of thing done?

Fresno is not the only town along the preferred route. If you slow down there, you'd have to do the same for Bakersfield, perhaps even Wasco, Lemoore, Corcoran, Hanford and Madera. Later on, trains would have to slow down through Merced, Atwater, Livingston, Turlock, Modesto, Manteca, Stockton, Lodi and Elk Grove. A couple of minutes here, a couple there, pretty soon you're talking about a significant time penalty.

Besides, even with recuperative braking, the energy cost of express travel would go up. A secondary consideration, but still.

@ wu-ming -

installing triple glazing in houses adjacent to the HSR tracks would be possible via grants and probably work better than a sound wall. Logistically, some bureaucrat would have to determine how much of a grant to award for each property. Those estimates will be disputed, so getting hundreds of homeowners to agree to such a plan might be harder than herding a bunch of cats.

I was under the impression that the proposed alignment would only pass through major cities like Fresno and Bakersfield. Upon closer inspection, it appears that it indeed passes through the smaller cities and towns you mentioned. Ideally the route would simply bypass these minor towns but I suppose there are some major ROW issues.

Frankly, I am not too concerned about noise issues with respect to using the same RR corridors that exist today.

HSR may be more frequent, but it sure sounds more quiet than current freight operations! The duration is also much shorter than freight. In fact, I suspect a comparison of the daily duration of high decibal noise between freight and HSR would show that HSR is comparatively nominal.

Regardless, persons or businesses that located adjacent to exisitng rail seem to have no standing when it comes to complaints about noise from trains; the tracks were there first. In these instances, I would not support any sound mitigation for those deemed affected.

But, new corridors are different. In these instances the environmental review process should identify impacts.. and if deemed that there are significan t impacts with regards to noise, then appropriate mitigation should be spelled-out.

there are lots of grade crossings in Europe and trains do not have to sound horns and ring bells multiple times at every single one of them.

The FRA rules on this are a direct result of personal injury lawyers suing the rail operators and, the federal government's desire to cover its legal backside. In the US, courts assume that liability lies with whoever has the most money, because that maximizes income for a legal profession that operates on the no-cure-no-pay principle.

That said, Congress has at least forced FRA to finalize its quiet zone rule, intended to give long-suffering communities a way to silence those infernal train horns and bells. It costs money, but so do useless stealth bombers. It's about priorities.

FRA's concept calls for communities to install proper safeguards at an unbroken sequence of grade crossings to ensure morons can't play chicken with mile-long freight trains by driving school buses around closing crossing gates.

@brandon - you make a good point, and having lived near the tracks in the past, i can say that the 15 minutes it took them to lumber past my neighborhood, blowing their horn intermittently, was annoying. But, I was saved by the fact that there were only 2 or 3 freight trains per day that passed my area. There are going to be upwards of 50 express trains whipping through these cities every day. That averages to 4 per hour for a 12 1/2 hour day. Not fun.

I'm not sure how many freight trains they get through Fresno & Bakersfield each day, but if it's less than 10 i'd say their overall annoyance is going to go up.

As Rafael mentioned, the sound walls will help, including for the freight trains (which were previously unmuffled). Also, the elmination of most grade crossings for the freight trains (I assume that's part of the deal for using their RoW, they'll get grade crossings eliminated too, right?) will help silence the bells & whistles that they usually generate.

But, i think it's still going to be an issue. Enough so that the commission should probably put some of the projected operating surplus towards buying up right of way for express trains to bypass Fresno and Bakersfield.

I trust that every option is being studied to route HSR tracks around smaller cities like Lemoore, Lodi & etc.

I recommend that you also check out this article (pdf!). The German Railways used 90 microphones for a much better spatial resolution.

It is quite spectacular how the main (lower front aerodynamic + first bogie wheel/rail, active, passive pantographs) and secondary sound sources (current connections, antennas, wheel/rail on other bogies, coolers) are visible for a 350 km/h run of the ICE-3 -- and nice how they identified a rubber tube as the strongest source at the leading bogie... (There are sound images for an Italian ETR500 and an older ICE-2, too.)

You can also use at reference values for various European high-speed and fast trains at different speeds and test tracks in this pdf (page 4, Table 1; of relevance are the "LpAeq,tp" values).

On your article, two notes.

First, the power electronics aren't likely to be significant sound sources at 330 km/h, the coolers would be much louder -- in this case certainly as the tested TGV Atlantique still has large side cooler grids.

Second, while aerodynamic noise is proportional to the cube of speed, it should also be mentioned that it is proportional to cross section, too. This favours the TGV (and other European products) against the wider-bodied (though lower) Shinkansens (though the AGV with its shorter cars is again wider). For the N700 series and JR East's FASTECH 360 S prototype, cross section was slightly reduced compared to their ancestors for noise considerations.

for reference, the total number of freight trains that run through Fresno every day is around 70. That's for UPRR, BNSF and SJVR combined. The greatest source of friction is BNSF traffic, because that alignment runs through a number of residential neighborhoods. Fresno has been trying to "persuade" BNSF to leave for 90 years but the city hasn't been willing/able to pay for a bypass.

@ DoDo -

thanks for the link to the German acoustic tomography study. It's of more recent vintage, so it was able to leverage more computing horsepower in the imaging.

Perhaps the most surprising result is that some of the loudest noise sources are ancillary equipment like rubber hoses and antennas. Cooling fans for the power electronics can also be extremely noisy, though I can't help but wonder why something traveling at 330km/h needs to run them at all. Formula 1 cars use pressurized coolant cycles (to raise the boiling point) and slanted radiators (to increase the surface area).

Stationary trains have no choice but to run fans, though perhaps engineers ought to pay more attention to the noise emitted by compressors and other ancillary equipment.

Wow. If they're used to 70 freight trains (or even if only half of those are on the HSR alighment), I think they'll be fine with some high speed trains going by too. Especially if it means the freights blow their whistles less frequently (due to fewer grade crossings).

It really is too bad we can't use the 500 series shinkansen. That's a really sexy train.

Gamecoug- I have lived near tracks in my life too. Trains and their horns are not fun; especially at 4am!

That said, when I realized my error when I moved to a location near tracks and was subjected to such noise.... I decided to move away as soon as practical, choosing to return after a planned quiet zone was implemented, rather than complain. I knew and felt I had no standing; the tracks were there first and their function trumped my choosing to live there.

----Btw, in Downtown San Diego a number of people began complaining about train noise (from freight, Amtrak, Coaster). People did not like the train horns in the middle of the night... and it seemed excessive in the minds of many.

Complaints resulted in meetings involving elected officials, city departments and the train oeprator.

When the freight operator reviewed their practices they realized that they were not sounding their horns per FRA requirements... and b/c they had more focus on themselves, began following the requirements more closely.

Ironically, that resulted in more horn blasts.

The city is now working to reconstruct many of the crossings so that a quiet zone can be implemented downtown. That will not completely remove horn blasts, but reduce the requirements upon operators.

Rafael, I'm glad TGVweb is still of use. I haven't updated it in nearly a decade :)

Running HSR through *any* town in the central valley is probably a move by the controlling stakeholders (construction companies) to build as many grade separations as possible, under a green-washed pretext of improving transit connections in urban cores. It is a stupid idea and will drive construction costs through the roof, fulfilling the worst fears of the Howard Jarvis crowd.

It would be much more effective to build lower-speed "sidings" to serve central valley towns; the trains that use them would be slowing down anyway, which takes care of the noise problem and the track alignment problem.

The noise is quite startling. The best analogy I have for it is a passing jet fighter.

The AGV cars are shorter (though also wider), and include composite materials. Though the AGV is close to 17 tons per axle, I note that the AGV demonstrator "Elisa" (photos) had a cross section suitable for Duplex, while the V150 world speed record train had Duplex middle cars fitted with the Elisa motor bogies yet the 16-axle train only weighed 234 tons, so an AGV Duplex may not be that difficult. The CEO of Alstom said recently that the AGV Duplex will come.

On the THSR 700T, is certification for 350 (rather than 300) km/h a typo? If not, could you give a source? At any rate, the new tilting JR West/JR Central Series N700 (in service from last year; has even better noise -- and nose -- design) does 300 km/h.

On the Talgo, a small terminology issue: the frames holding pairs of single wheels on stub axles are called "portals". The "Jacobs configuration" involves a bogie. I also note that though the name is Talgo350, due to insufficient power (and probably also unsatisfying ride quality at the highest speeds), the trains are certified for 330 km/h only.

Talgos (if we also include the UAV TurboTrain, after all a Talgo derivative) aren't the only passive tilting trains, there are for example the first Japanese tilting trains (they introduced active tilt due to the annoying delay of passive tilt).

Clem, I would prefer a more expensive routing with stations in city centres to more Haute Picardie-style stations... methinks France and SNCF went too much for low-cost on this. (Then again, you could cite Italy for your position.)

As a general comment on the whole debate: for noise considerations, I think a cut-and-cover tunnel under the most densely populated area would be sensible. (Even the low-speed city access in Zaragoza was put in such a tunnel.)

You made a note about the noise being concentrated in the undercarriages of the power cars. That would be good incentive to use EMUs such as the JR700 and the AGV since all the cars distribute the power and therefore the noise.

@Clem:

There was good reason to run the HSR lines through the center of the CV cities -- to serve those cities. Its a law of transit that for the system to be successful, you have to service the most ideal locations -- in CAHSR's case, the CV urban core. The obvious downside of that is the grade-separations that are necessary. But I do not think that choosing routing through those city centers is a result of construction co lobbying. While it may drive costs through the roof, its also necessary for the HSR line to be successful.

Part of the purpose of the CAHSR was, in addition to serving the LA-Bay line, to serve the CV communities who are emerging as economic centers in California. It would really be foolish to bypass them.

What do you mean by lower speed sidings? A siding in the traditional sense, is a track that deviates from the maintracks on the line for a given distance for the purpose of storing vehicles or bypassing trains (going with or going against). So I'm not exactly sure what you mean.

If you mean build the HSR line around the city and build a lower speed *branch* to the urban core, that's a perfect way to drive up costs (moreso than aligning HSR through the city center).

There have been a lot of discussions here about how the city center approach should work. I think the general consensus is that the HSR trains should join the Legacy ROW (not necessarily the legacy tracks) at the edge of the city and use that until they get to the station and get back out to the countryside.

One of the common misunderstandings I hear is that people are afraid that these trains will rush at 220mph through the center of the city. 220mph is a max speed objective for the countryside. In the urban areas it will reduce speed just as it does everywhere else in the world.

I don't think it's appropriate to assert that just because Fresno residents have had to put up with intolerable noise for the last 90 years, it's perfectly fine to subject them to more of the same. HSR is supposed to be a major improvement for everybody, not just people in SF and LA.

There is a lot of confusion about the speeds at which trainset manufacturers certify their products for commercial service and those at which operators actually deploy them. To the best of my knowledge, the conservative approach is due primarily to concerns about the absolute dependability of wireless signaling systems. Taiwan did build the infrastructure for 350km/h, but they are not (yet) running trains any faster than 300km/h.

Perhaps the higher electricity consumption and other factors also prompt operators not to exploit their rolling stock to the advertised limit. Speed record runs are purely for marketing purposes, of course.

good content never dies, it doesn't even fade away :-) E.g., this funny nugget from MSNBC's Rachel Maddow show.

Wrt to your pet peeve about those evil, evil civil engineers always wanting to pour more concrete: I created a MAP to explore the idea of an Italian-style direttissima for the Central Valley, plus detours to reach the downtown areas of Stockton, Fresno and Bakersfield.

Result: the express section is just as long as the one proposed by CHSRA (~365mi), but requires a lot of new ROW through prime farmland. And yes, FRA requires full grade separation for all tracks rated at or above 125mph, regardless of road traffic volume.

The detour sections add another 80+ miles. FRA rules on mixed traffic mean that without a waiver, those detours would also have to be brand-new dedicated tracks as well. Full grade separation could perhaps be avoided only if a speed limit of 125mph or less is imposed, but around 75% of all trains (i.e. approx. 150 a day) will stop in Fresno and, almost as many in Bakersfield. Only the 50 or so express trains would bypass them. That leaves a lot of opportunities for dipstick motorists to cause accidents.

Ergo: CHSRA is actually not trying to maximize the amount of civil engineering work. It just has to live with FRA rules regarding grade separations and mixed traffic.

(1) Afaik, the Talgo 350 is currently the only high speed train capable of ~220mph that only has motors in the tractor cars at either end. The Siemens Velaro, all the Japanese designs, the AGV - all EMU designs. Distributing the noise sources reduces peak sound power levels but as I tried to explain, that's not all that matters. The duration of exposure also factors into the equation, so I think exterior noise is a poor reason for choosing an EMU. Interior noise is actually worse.

An EMU config does permit increasing the power/train weight ratio without exceeding the axle load limit of 17 metric tons.

(2) "One of the common misunderstandings I hear is that people are afraid that these trains will rush at 220mph through the center of the city. 220mph is a max speed objective for the countryside. In the urban areas it will reduce speed just as it does everywhere else in the world."

I haven't read that in any of CHSRA's publications, but perhaps I missed something. Can you provide a reference please?

the oil- or water-cooled power electronics and transformator are at the center of a loco resp. on the underside of a distributed-power multiple unit, you have to get the heat out somehow. To boot, the traction motors need even more cooling power (they have individual coolers). There, you rather have air cooling, and you definitely need more cooling at higher speeds. You also want to emit hot air above the heads of passengers waiting on platforms, hence, the development of 'cooling towers'.

That old TGV set indeed has compressors as loud as that of 40-year-old locomotives here in Hungary... yet, even the latest regulation on train noise we have, the EU's TSI-Noise (2006/66/EC), explicitely excludes compressors from stationary noise requirements...

Another problem with the bypass option is that these cities will continue to grow. If we try to put bypass tracks around these cities and they continue to grow like they have been, then soon the city growth will overtake the tracks and we'll need new sound walls built along the bypass tracks.

I shall emphasize again that for exterior noise, motor noise is not the dominant factor. Already at intermediate speeds, wheel/rail dominates it. At high speeds, aerodynamic noise will dominate even wheel/rail. You won't change much with distributed vs. tractor head power -- except for interior noise, as Rafael says.

@ Rafael,

Ah, thanks for giving the source. This may be a mistake spreading through the web via Wikipedia (I just corrected the page: the source they cite said 300 km/h). The figure is certaily wrong, because certified top speed needs test runs at a higher speed, and the train only got to 315 km/h. (In Europe, the rule is: tests until certified speed +10%, so we would not let them go faster than 285 km/h...)

Service speeds below certified speeds (as for the Talgo350 and Velaro-E in Spain, or the ICE-3 in Germany: the first and last 300 vs. 330, the middle 300 vs. 350 km/h) are another issue, but I agree entirely on the reasons.

Ah. I had a hunch as to the source of the 350 km/h figure, and found it. It's the design speed of the line. See track manufacturer article (pdf!). I updated the Engish Wikipedia with this (and noticed that Japanese and Chinese Wikis were correct).

your notion that sprawl will ultimately engulf any train alignment, so you might as well run it through the existing downtown is deeply flawed IMHO.

First, it is by no means certain that 20th century patterns of car-centric development will continue in the 21st century. Oil is cheap right now, but in a few years the global economy will recover and $4+ gas will be back. In fact, if US politicians were actually thought leaders, they would argue that a rapidly rising floor price for all petroleum products is exactly what is needed to create a market for innovative green tech products and services that cannot be offshored. Reduced dependence on foreign oil/need for military action to secure access to it and, reduced GHG emissions would be hugely valuable fringe benefits.

Second, there is value in putting stakes in the ground that discourage sprawl or at least, slow it down. Cheap gas plus easy mortgage credit plus overly generous tax deductions for mortgage interest are what led to the McMansion boom and now, bust.

@ DoDo -

ok, so Taiwan expects to run trains at 350km/h at some point, but one or more technical limitation prevent that at this point. I don't believe for a moment that Japanese engineers don't know how to build a train that can run at that speed, so I still suspect the wireless signaling is the weakest link right now.

Wrt cooling, water beats oil in terms of specific heat capacity. I see no fundamental reason why trains could not feature F1-style pressurized radiators and air scoops on their roofs. EMU designs would lend themselves especially well to the approach, because the heat losses are distributed over the length of the train.

The Japanese did not make the mistake of trying wireless like we in Europe. From what one reads about the FASTECH program, it's the failure to achieve the bold goals in noise and stopping distance reduction that compelled JR East to bury its ambitions. The 700T never had that ambition: insufficient power. However, you yourself quoted Kawasaki's efSET, so ambition is surely not dead in Japan.

Water also beats oil for environmental reasons (at least that featured prominently in ADtranz and Siemens marketing when they switched to water cooling with their GTO thyristors in the nineties). You can't water-cool the motors, so that'll remain air-cooled.

I'm not entirely sure that's correct. While it's obviously important to avoid short circuits, the magnetic cores of the stator could be hollow to support a coolant circuit.

For the rotor of permanent magnet synchronous machines (e.g. Alstom AGV), water cooling would be more difficult but not fundamentally impossible. Essentially, you'd need a hollow shaft containing some non-structural insulated coolant distribution plumbing, coolant channels embedded in the sintered magnets and a sealing system to avoid leakage at the shaft interfaces of inlet and outflow. Both of those would be located at the unloaded end of the shaft.

I don't know if anyone actually produces such a beast right now, though.

I don't think it's appropriate to assert that just because Fresno residents have had to put up with intolerable noise for the last 90 years, it's perfectly fine to subject them to more of the same. HSR is supposed to be a major improvement for everybody, not just people in SF and LA.

I agree that we're trying to improve life for everyone involved. However, as you mentioned, the rail lines have been there for 90 years. The people who moved there did so knowing they were going to be subjected to noise from the nearby train tracks. My point is, if they add soundwalls to cut everyone's noise, plus remove grade crossings so the freights don't blow their whistles all the time, the net will be an improvement to their standard of living.

I agree that in a perfect world they should do a freight & HSR bypass (for many reasons, not just sound), but I don't think it's essential, and I don't think the CAHSR project is going to ruin the lives of people who live near the track. That's my point.

The cut/cover trench idea is very interesting. I wonder what the cost comparison looks like.

The proposed path from San Francisco to San Jose down the peninsula through San Mateo County is said to require a minimum right of way of from 100 to 150 feet in width along with grade separation. Currently of the 24 miles the rails will traverse, more than one third, about 8+ miles have a right of way now of about 65 feet. With the requirement mandating dedicated tracks for HSR creating 4 parallel sets of tracks down the length of the county and the peninsula, how much is the acquiring of land through eminent domain going to cost? How long will the acquisition process take, and how many of the 14 some odd small cities and hundreds of land and business owners along this length are going to challenge in court what CHSRA will try and do? How long will these delays become? There will have to be by statute environmental impact studies for each legally recognized independent political and private entity. Is the moving forward of this project going to take years, decades or centuries?

Putting the line underground reduces the noise problem, but doesn't eliminate it. I don't have precise figures, but I live right on top of a subway line, and I can hear and feel the vibrations; at subway speed it's nothing serious, but at 350 km/h, there will be problems.

The cost of new subway construction in LA and SF is about $200 million per two-track km. For about 5 km of subway in Fresno, this works out to $1 billion.

I heard that part of the idea of going through downtown Fresno with cut and cover was that the air rights could be leased (in a way similar to the rights over the yard at Grand Central in New York) and thus recoup some of the costs, particularly if land values go up near the station.

Regarding the noise supression of cut and cover - I'm aware of the noises and vibrations from NY subways: I find 'em tolerable. The two-layer BART and MUNI under Market Street in SF is also cut and cover; having worked on Market Street for a few years, I found the noise/vibration negligible.

In cut and cover all that noise at 350kph has got to go somewhere - but with fireproof sound absorbing walls and ceilings and tracks on rubber pads and spaces to absorb the shock waves of passing trains what kind of sound levels are we talking about?

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